Various internet protocol (IP)-based wireless packet access networks exist at the same time, such that a next-generation wireless network will be evolved to a type having an overlapped service area.
The multiple wireless network systems have different characteristics, and service areas of the wireless networks that interwork with each other are hierarchically overlapped to allow a service subscriber to access an optimum network depending on a position, a radio wave environment, a service characteristic, and a subscriber's preference.
In the multiple wireless networks, in order to provide optimum performance and a seamless service to the service subscriber, it is very important to support inter-RAT handover that converts a connection path of a service that is progressed by the optimum wireless network depending on the position and the radio wave environment of a multi-mode mobile station.
In order to support the inter-RAT handover, a process in which the station detects wireless networks that are serviceable at a current position of the station by recognizing not the radio wave environment of the network that is serviced but a radio wave environment of another network should first occur.
Further, the serviceable wireless networks should be rapidly detected in order to provide a broadband data transmission rate to a station having high-speed mobility and power efficiency.
The multi-mode station for supporting the multiple wireless networks includes modem modules for each wireless connection technology and power consumption increases or it is difficult to rapidly detect the wireless network depending on an operation mechanism for activating multiple modems at the time of detecting the wireless network.
A basic method for detecting the wireless network measures the intensity of a signal received from the wireless networks by continuously activating a plurality of wireless connection interfaces in the multi-mode station, and remarkably increases the power of the multi-mode station in an area where the wireless network cannot be accessed. Accordingly, a method of periodically activating the plurality of wireless connection interfaces in the multi-mode station is proposed, but opposed influences are given to rapidity of the network detection and efficient power usage depending on activation cycle of the wireless connection interface. That is, when the activation cycle of the wireless connection interface is set to be shorter, the network can be rapidly detected but the power consumption of the multi-mode station increases, and when the activation cycle of the wireless connection interface is set to be longer, the power consumption of the multi-mode station can be decreased but it is difficult to rapidly detect the network.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.